The goal of this study is to discriminate the effect of exercise training, changes in body composition and changes in dietary intake on coronary risk factors in a coronary population. The study population consisted of 122 patients who had recently suffered a coronary event who were entering the outpatient cardiac rehabilitation program. Data collection included measures of fitness such as peak aerobic capacity, body composition, body fat distribution and measures of coronary risk factors such as lipid profiles, glucose and insulin measures. Before conditioning, it was found that measures of body fat distribution were the best predictors of coronary risk factors in older women with coronary heart disease. In male coronary patients this situation is somewhat different as it was found that in contrast to women, general measures of obesity such as body weight, body mass index and fat mass best predicted coronary risk factors. In response to 3 months of cardiac rehabilitation exercise conditioning males decreased fat mass and waist circumference to a greater degree than women. Both men and women increased their HDL levels whereas other lipid subfractions, glucose and insulin levels were unchanged. Patients with the most abnormal measures of certain lipid subfractions, such as patients with triglyceride values over 250 mg/dL, experienced a significant 25% decrease in this measure after conditioning. Changes in risk factors after conditioning were not closely associated with changes in body composition or body fat distribution.